CDC Principles of Epidemiology - Lesson 3 Flashcards
Proportionate mortality
Formula: Proportionate Mortality = (Deaths caused by a particular cause / Total deaths in the population) * 100%
Represents: The proportion of deaths in a specified population over a period of time attributable to different causes.
Ratio
Formula: Ratio = Comparison of two quantities that have the same units of measurement.
Represents: A comparison of two quantities that have the same units of measurement.
Proportion
Formula: Proportion = A ratio that compares a part to a whole.
Represents: A ratio that compares a part to a whole.
Rate
Formula: Rate = A ratio with different units of measurement.
Represents: A ratio with different units of measurement.
Incidence
Formula: Incidence = The occurrence of new cases of disease in a population in a given period of time.
Represents: The occurrence of new cases of disease in a population in a given period of time.
Incidence Proportion or Attack Rate
Formula: Incidence Proportion = (Number of new cases of disease / Size of the population at the start of the period) * 100%
Represents: The proportion of a population that develops the disease during a specific period.
Incidence Rate (or Person-Time Rate)
Formula: Incidence Rate = (Number of new cases of disease / Total time each person was observed) per person.
Represents: A measure of incidence that incorporates time into the denominator.
Prevalence Rate
Formula: Prevalence Rate = (All new cases and pre-existing cases during a given time period / Population during that time period) * 100%
Represents: The proportion of people in a population who have a specific disease at a specified point in time or over a specified period of time.
Mortality Rate
Formula: Mortality Rate = (Deaths occurring over a specific time period / Size of the population among which the deaths occurred) * 1000 (commonly)
Represents: The measure of the frequency of occurrence of death in a defined population during a specified time interval.
Crude Mortality Rate
Represents: Mortality rate from all causes of death for a population.
Cause-specific Mortality Rate
Represents: Mortality rate from a specific cause.
Age-specific Mortality Rate
Represents: Mortality rate limited to a specific age group.
Infant Mortality Rate
Formula: Infant Mortality Rate = (Number of deaths among children < 1 year of age / Number of live births) * 1,000 (commonly)
Represents: The rate of death among infants under one year of age.
Neonatal Mortality Rate
Formula: Neonatal Mortality Rate = (Number of deaths among children under 28 days of age / Number of live births) * 1,000 (commonly)
Represents: The rate of death among neonates.
Postneonatal Mortality Rate
Formula: Postneonatal Mortality Rate = (Number of deaths among children aged from 28 days to 1 year / Live births in the same time period) * 1,000 (commonly)
Represents: The rate of death among children aged from 28 days to 1 year (non-inclusive).
Maternal Mortality Rate
Represents: Mortality of maternal mothers.
Sex-specific Mortality Rate
Represents: Mortality rate of one sex.
Race-specific Mortality Rate
Represents: Mortality rate of one race.
Death-to-Case Ratio
Formula: Death-to-Case Ratio = (Number of deaths attributed to a particular disease during a specified time period / Number of new cases identified of that disease during the same time period) * 100%
Represents: The ratio of deaths to new cases of a particular disease during a specified time period.
Case-fatility Rate
Formula: Case-Fatality Rate = (Number of deaths from that case / Number of cases) * 100%
Represents: The proportion of people with a particular condition who die from that condition.
Natality Measures
Represents: Population-based measures of birth.
Risk Ratio or Relative Risk
Formula: Risk Ratio = (Risk of disease in the group of primary interest / Risk of disease in the comparison group)
Represents: Compares the risk of a health event among one group with the risk among another group.
Rate Ratio
Formula: Rate Ratio = (Rate for the group of primary interest / Rate for the comparison group)
Represents: Compares incidence rates, person-time rates, or mortality rates of two groups.
Odds Ratio
Formula: Odds Ratio = (AD/BC)
Represents: A measure of the relationship between an exposure with two categories and health outcome.
Attributal Proportion
Formula: Attributable Proportion = ((Risk for exposed group - risk for unexposed group) / Risk for exposed group) * 100%
Represents: A measure of the public health impact of a causative factor.
Vaccine efficacy or effectiveness
Formula: Vaccine Efficacy = (Risk among unvaccinated group - Risk among vaccinated group / Risk among unvaccinated group)
Represents: The proportionate reduction in cases among vaccinated people.
YPLL
- Calculation from line listing
Decide on end point
Exclude all people who died at or after the endpoint
Calculate YPLL for all people who died before the end point by subtracting the age at death from the end point
YPLLIndividual = endpoint - age of death
Sum the individual YPLLs - Calculation from a frequency
Eliminate all age groups older than the endpoint
For each age group left, identify the midpoint of the group
Youngest + oldest + 1 / 2
Identify the YPLL of all ages younger than the endpoint by subtracting the midpoint from the endpoint
Calculate age-specific YPLL by multiplying the age group’s YPLL times then number of people in that age group
Sum these YPLLs
YPLL Rate
YPLL / population under the endpoint
